Thread: v8 swap

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hey guys! i am new here. i am planning a small block chevy swap into my 84 mazda rx 7 gs. i wanted to know what engine setup you guys think i should run with. we were going to go with a 383 but think the torque would be hard to hook up with. I am more interested in building a SBC that can hold higher rpms,6000-6500when racing, and has more horsepower than torque. the car will only be about 2500 pounds with me in it and the size of rear tires is limited, so i don't need all that torque. the highest compression i would run is 9 to 1 and it wil have ported aluminum heads and huge exhaust. the plan for this year is to drop the engine in and get everything squared up. next year maybe a low sitting supercharger or a switch from carb to fuel injection & turbo setup. thanks for any input you could give.

i am planning un using thier swap kit. it is just the odds and ends though. motor mounts and oil pan etc. what i am asking is what kind of buildup should i do for a bulletproof lowcompression SBC that can handle 6000 - 6500 rpm's when racing? i am more concerned with horsepower also instead of torque. no matter what build up i have a SBC will have more than enough torque to launch a car weighing in at 2336 pounds. right now from what i have gathered info wise i need very strong rods and gaskets. what else? should i go with a 350, 383, or a destroked SBC? any info is appreciatted! thanks!

with a little more research we are now looking at a chevy 302 or 327 and a t56 6 speed tranny. alot of guys use these for track engines and they are supposed to handle some high rpm's. what do you guys think?

i want this to be a all around good street car. i am focused on a lowcompression short stroke engine that can handle high rpm's because in a year we plan on a twin turbo set up for it. we want to 1st get all the quirks out of it and set up a good way to hook up traction. with the wieght advantage i don't need tons of torque to make me launch in any gear. a junkyard SBC could launch this thing. i am also wanting reliability and for this car to be able to road race. the rx 7 have a huge line of road racing products but there is no way i am staying rotary. they get the same gas mileage as a built 350 and have only 1.3 liters! anyway a overkill in torque will just spin the tires off. i want high r's so i can hold in the gears longer. why what do you guys think i should run with?

you can read the article about the two competing if you want at granny'smotorsports-
7-23-04...V-8 powered RX-7s in Grassroots Motorsports Magazine...
...The August 2004 issue of Grassroots Motorsports Magazine features quite a few V-8 powered RX-7s that entered their $2004 Challenge event in Florida. The premise of the event is to build the best handling, best appearing, and quickest car possible for a total budget of $2004., including the price of the car and all components. You will be surprised at the wide variety of entrants and how creative they are. Of a total of 76 cars that participated, a total of 9 RX-7s took part in the event, 5 V-8 powered and 4 rotary powered...
...In the drag race portion, all the V-8 RX-7s finished ahead of the rotary powered cars. No surprise here. The quickest V-8 RX-7 recorded a 12.636 ET, the quickest rotary's ET was a 14.323.
...What WILL suprise a lot of sports car people is the results of the autocross competition. The quickest RX-7, a V-8, finished nearly 4 seconds ahead of the quickest rotary version. Among the 9 RX-7s present in the autocross, V-8 power captured 4 of the top 5 spots. Don't listen to those who tell you that a big V-8 will ruin your handling!!!

there it is! are you thinking i won't be able to? a stock 350 could easily smoke a rotary at the drags. i just want to make this a all around car. i want a manual and a engine that revs high. this is what i am used to from previous cars. i am not trying to compete with anyone but as far as that goes once done there will be few street cars that can touch it. i just wanted to know what setup you guys would recommend. yes the rotarys are lighter but with a 160 HP who cares! they can play on the skid pad all day. suspension parts are already made for the v8 conversions so i will be able to handle pretty decent.

302s of any kind are hard to find. The dirt track racers here have a new class that is restricted to 302 and 305 Chevy motors. Just about all the 302s around here have been scooped up. You can build one using a small main 327 block and a 283 crank. But I think I would build a medium journal 327. Any 350 block will work. I don't think you will need four bolt mains but if you think you do then a 350 block is what you want. You will also need a medium journal 327 crank. They are not hard to find. A lot of medium journal 327s have been rebuilt using 350 cranks. If you can not find one I can help you out.

my friend has done this....it works good.. it has a huge cowl hood and he has alot of heating problems...

we were originally going with a 383 but i wondered if the long stroke would cooperate with a turbo boosted engine. The ONLY reason i am thinking short stroke is because i am thinking in the line of forced induction later. V8's are a whole new ball game to me. my dad is in to old school chevy carb'd v8's and i am into anything that makes power. i learned my engine performance from a 98 eclipse turbo so i have a whole new set of rules to learn . i am just trying to take a light car big engine and add handling. the goal of every performance car. alot of guys around here told me 350's only rev to about 4k or 5k rpm before shifting. i want a manual so i can control this, plus it is what i am used to. i like road racing also so it is needed. everyone says get a turbo 350 but this is not good for holding rpm's in the corners. i respect it's strength but it's not what i need. a guy slapped a 350 crate engine with a 130 shot of nitrous into one of these cars with slicks and was running mid 11's. his turbo 350 was running out of gear at 98 mph!! he changed the gears and ran high 10's! awesome. i know nothing about a muncie 4 speed but i will look into it thanks to you. I want to stay small block but i do want the most cubic inches that can handle boost. any info you guys can give me will be great because i am still learning. thanks!

we are going to cut away the top part of the firewall were it is vented to the outside for air. it should work like a reverse cowl hood. i am also going for the heavy duty radiator they sell for the swap, the biggest oil cooler i can mount, and exhaust wrap for the headers. any other ideas on how to keep it cool?

sorry about the confusion. i knew the difference. I want the 6 speed and everyone around here is telling me to go 350 turbo because of cheapness and strength. i don't think i will need all those gears either. i thought it would be sweet to get it set to were the 5th gear would be a good high cruising speed for the highways and to make the 6th gear tall just to see how fast i could get her. you are right about the length of stroke for turbocharged vehicles though. on the 2.0 in my old car you could stroke up to a 2.4 but people would meet in the middle for a 2,2 because the 2.4 would get crazy rod angles at high rpm's. Destroying the engine in the process. i made the mistake of applying this too all engines. thanks for straightening that up. do you think the top end idea for the 6th gear could work or am i over looking something? the car is extremely streamlined and just thought it would be something extra. beside how many people can say there rx7's have close to 400 cubic inches and 6 gears?

p.s. they also have narrowed ford 9 inch or mopar 8 3/4 rear ends with everything to bolt right up. i believe i am going with the ford 9 inch. you know this could end up being a monster of a car!

the tranny's that would be easiest to go with are these four. t-350, t-400, t-56, and a 200r4. They all will allow the gearshift to come up through the stock shift boot and granny's motorsport makes custom driveshafts for them. i also for got that i am trying to keep the car as stock looking as possible. it already sits low. i don't want a damn body kit and i will shoot myself before i add a spoiler or wing. i am adding 2 inch fender flares to help hide the rubber i will need to hook up. besides that and the rumble of the engine it should appear stock. that is another reason i am going for the turbo's because i don't want a supercharger sticking out the hood. if you have that there goes 90 percent of your races. i love the sleeper theme and i am going to stick with it. thanks to everyone here who is giving me info, i appreciate it.

Here's some other numbers for you to ponder.....


Mustang Cobra = 13.3 lbs per HP
Camaro Z-28 = 12.3 lbs per HP

Viper / ZR1 = 8.6 lbs per HP

Monster Miata = 10.9 lbs per HP

Mega Monster Miata (supercharged version) = 7.0 lbs per HP

1st gen rx7 LBS/HP = 7.14 lbs per HP (2500 lbs / 350 hp Chevy V8

HOW IS THAT FOR A COMMERCIAL!

THAT IS WITH A STOCK 350, NO WEIGHT REDUCTION.
thanks for the info techinspector1. I will check them out. also granny's site host another web page engine swaps.com. they have everything from cadilac northstar fiero's to a jeep wrangler with a viper v-10 in it! i love the horsepower junkies who stay openminded to the possibilities! thanks for the help!